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Thu, 20 Nov 2025 07:43:53 -0800 (PST) Received: from ALA-EXCHNG02.corp.ad.wrs.com (10.11.224.122) by ALA-EXCHNG02.corp.ad.wrs.com (10.11.224.122) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.61; Thu, 20 Nov 2025 07:43:53 -0800 Received: from pek-lpd-ccm6.wrs.com (10.11.232.110) by ALA-EXCHNG02.corp.ad.wrs.com (10.11.224.122) with Microsoft SMTP Server id 15.1.2507.61 via Frontend Transport; Thu, 20 Nov 2025 07:43:51 -0800 From: Yun Zhou To: CC: , , , , , , , Subject: [PATCH] jfs: add dtroot integrity check to prevent index out-of-bounds Date: Thu, 20 Nov 2025 23:43:50 +0800 Message-ID: <20251120154350.1041513-1-yun.zhou@windriver.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Authority-Analysis: v=2.4 cv=BqiQAIX5 c=1 sm=1 tr=0 ts=691f3739 cx=c_pps a=Lg6ja3A245NiLSnFpY5YKQ==:117 a=Lg6ja3A245NiLSnFpY5YKQ==:17 a=6UeiqGixMTsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=t7CeM3EgAAAA:8 a=WdL6VqjaRq5tQHEv-3AA:9 a=FdTzh2GWekK77mhwV6Dw:22 X-Proofpoint-GUID: Eqw-Bb_E5Q6QSoS6FmAzDbHwJBS22LcC X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMTIwMDEwMyBTYWx0ZWRfX2FSRmxeFkKC4 iMmD/brP2uN52gkuUXwe854L0vCXemEma1/FnE9ssBzLs9qlRe4jZsVpWZWRo5kTk4rnc8EWmC4 dB1A0Hx2DdlZGm1fLpxFotEIkozqC8o4d92YOjB/JOh3AR/CS/J/nu7TWDfjsEVWn69xpQzJ/2j SvQ6sTyGRkcyPFdoIN8bJ77NvwStUntY8iIBT5kw9970bfPrvJ+hLPYiB6I43h/vQ13AYCQhed4 j5eUi9tdVGrl9A2qMwGxouwEY7e+u7knQDOtJz8sQvPJDwXm8DywIhMZ/ZfzT543AWycRAKLh4Q 3lMbpe+g969tOVPJszoYMlrRUTX8IglTjPMw5Yu32P2apBJQpCQPQS+EZ694Ab9NF+oPcmwPLbq m+/x7u4iE+G7x4VTIlMfKMZ6UeFuaQ== X-Proofpoint-ORIG-GUID: Eqw-Bb_E5Q6QSoS6FmAzDbHwJBS22LcC X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.100.49 definitions=2025-11-20_05,2025-11-20_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 phishscore=0 priorityscore=1501 suspectscore=0 adultscore=0 lowpriorityscore=0 impostorscore=0 malwarescore=0 spamscore=0 bulkscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2510240001 definitions=main-2511200103 Content-Type: text/plain; charset="utf-8" Add check_dtroot() to validate dtroot_t integrity, focusing on preventing index/pointer overflows from on-disk corruption. Key checks: - freecnt bounded by [0, DTROOTMAXSLOT-1] (slot[0] reserved for header). - freelist validity: -1 when freecnt=3D0; 1~DTROOTMAXSLOT-1 when non-zero, with linked list checks (no duplicates, proper termination via next=3D-1= ). - stbl bounds: nextindex within stbl array size; entries within 0~8, no duplicates (excluding idx=3D0). Invoked in copy_from_dinode() when loading directory inodes, catching corruption early before directory operations trigger out-of-bounds access. This fixes the following UBSAN warning. [ 101.832754][ T5960] ------------[ cut here ]------------ [ 101.832762][ T5960] UBSAN: array-index-out-of-bounds in fs/jfs/jfs_dtree= .c:3713:8 [ 101.832792][ T5960] index -1 is out of range for type 'struct dtslot[128= ]' [ 101.832807][ T5960] CPU: 2 UID: 0 PID: 5960 Comm: 5f7f0caf9979e9d Tainte= d: G E 6.18.0-rc4-00250-g2603eb907f03 #119 PREEMPT_{RT,(fu= ll [ 101.832817][ T5960] Tainted: [E]=3DUNSIGNED_MODULE [ 101.832819][ T5960] Hardware name: QEMU Ubuntu 25.04 PC (i440FX + PIIX, = 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 101.832823][ T5960] Call Trace: [ 101.832833][ T5960] [ 101.832838][ T5960] dump_stack_lvl+0x189/0x250 [ 101.832909][ T5960] ? __pfx_dump_stack_lvl+0x10/0x10 [ 101.832925][ T5960] ? __pfx__printk+0x10/0x10 [ 101.832934][ T5960] ? rt_mutex_slowunlock+0x493/0x8a0 [ 101.832959][ T5960] ubsan_epilogue+0xa/0x40 [ 101.832966][ T5960] __ubsan_handle_out_of_bounds+0xe9/0xf0 [ 101.833007][ T5960] dtInsertEntry+0x936/0x1430 [jfs] [ 101.833094][ T5960] dtSplitPage+0x2c8b/0x3ed0 [jfs] [ 101.833177][ T5960] ? __pfx_rt_mutex_slowunlock+0x10/0x10 [ 101.833193][ T5960] dtInsert+0x109b/0x6000 [jfs] [ 101.833283][ T5960] ? rt_mutex_slowunlock+0x493/0x8a0 [ 101.833296][ T5960] ? __pfx_rt_mutex_slowunlock+0x10/0x10 [ 101.833307][ T5960] ? rt_spin_unlock+0x161/0x200 [ 101.833315][ T5960] ? __pfx_dtInsert+0x10/0x10 [jfs] [ 101.833391][ T5960] ? txLock+0xaf9/0x1cb0 [jfs] [ 101.833477][ T5960] ? dtInitRoot+0x22a/0x670 [jfs] [ 101.833556][ T5960] jfs_mkdir+0x6ec/0xa70 [jfs] [ 101.833636][ T5960] ? __pfx_jfs_mkdir+0x10/0x10 [jfs] [ 101.833721][ T5960] ? generic_permission+0x2e5/0x690 [ 101.833760][ T5960] ? bpf_lsm_inode_mkdir+0x9/0x20 [ 101.833776][ T5960] vfs_mkdir+0x306/0x510 [ 101.833786][ T5960] do_mkdirat+0x247/0x590 [ 101.833795][ T5960] ? __pfx_do_mkdirat+0x10/0x10 [ 101.833804][ T5960] ? getname_flags+0x1e5/0x540 [ 101.833815][ T5960] __x64_sys_mkdir+0x6c/0x80 [ 101.833823][ T5960] do_syscall_64+0xfa/0xfa0 [ 101.833832][ T5960] ? lockdep_hardirqs_on+0x9c/0x150 [ 101.833840][ T5960] ? entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 101.833847][ T5960] ? exc_page_fault+0xab/0x100 [ 101.833856][ T5960] entry_SYSCALL_64_after_hwframe+0x77/0x7f Signed-off-by: Yun Zhou --- fs/jfs/jfs_dtree.c | 83 ++++++++++++++++++++++++++++++++++++++++++++++ fs/jfs/jfs_dtree.h | 2 ++ fs/jfs/jfs_imap.c | 4 +++ 3 files changed, 89 insertions(+) diff --git a/fs/jfs/jfs_dtree.c b/fs/jfs/jfs_dtree.c index d9cf2071c41f..e1cbc3a04f3f 100644 --- a/fs/jfs/jfs_dtree.c +++ b/fs/jfs/jfs_dtree.c @@ -4316,3 +4316,86 @@ int dtModify(tid_t tid, struct inode *ip, =20 return 0; } + +bool check_dtroot(dtroot_t *p) +{ + DECLARE_BITMAP(bitmap, DTROOTMAXSLOT) =3D {0}; + int i; + + /* freecnt cannot be negative or exceed DTROOTMAXSLOT-1 + * (since slot[0] is occupied by the header). + */ + if (unlikely(p->header.freecnt < 0 || + p->header.freecnt > DTROOTMAXSLOT - 1)) { + jfs_err("Bad freecnt:%d in dtroot\n", p->header.freecnt); + return false; + } else if (p->header.freecnt =3D=3D 0) { + /* No free slots: freelist must be -1 */ + if (unlikely(p->header.freelist !=3D -1)) { + jfs_err("freecnt=3D0, but freelist=3D%d in dtroot\n", + p->header.freelist); + return false; + } + } else { + int fsi, i; + /* When there are free slots, freelist must be a valid slot index in + * 1~DTROOTMAXSLOT-1(since slot[0] is occupied by the header). + */ + if (unlikely(p->header.freelist < 1 || + p->header.freelist >=3D DTROOTMAXSLOT)) { + jfs_err("Bad freelist:%d in dtroot\n", p->header.freelist); + return false; + } + + /* Traverse the free list to check validity of all node indices */ + fsi =3D p->header.freelist; + for (i =3D 0; i < p->header.freecnt - 1; i++) { + /* Check for duplicate indices in the free list */ + if (unlikely(__test_and_set_bit(fsi, bitmap))) { + jfs_err("duplicate index%d in slot in dtroot\n", fsi); + return false; + } + fsi =3D p->slot[fsi].next; + + /* Ensure the next slot index in the free list is valid */ + if (unlikely(fsi < 1 || fsi >=3D DTROOTMAXSLOT)) { + jfs_err("Bad index:%d in slot in dtroot\n", fsi); + return false; + } + } + + /* The last node in the free list must terminate with next =3D -1 */ + if (unlikely(p->slot[fsi].next !=3D -1)) { + jfs_err("Bad next:%d of the last slot in dtroot\n", + p->slot[fsi].next); + return false; + } + } + + /* Validate nextindex (next free entry index in stbl) + * stbl array has size 8 (indices 0~7), so nextindex must be within this = range + */ + if (unlikely(p->header.nextindex >=3D ARRAY_SIZE(p->header.stbl))) { + jfs_err("Bad nextindex:%d in dtroot\n", p->header.nextindex); + return false; + } + + /* Validate index validity of stbl array (8 elements) + * Each entry in stbl is a slot index, with valid range: -1 (invalid) or = 0~8 (slot[0]~slot[8]) + */ + for (i =3D 0; i < p->header.nextindex; i++) { + int idx =3D p->header.stbl[i]; + if (unlikely(idx < 0 || idx >=3D 9)) { + jfs_err("Bad index:%d of stbl[%d] in dtroot\n", idx, i); + return false; /* stbl entry points out of slot array range */ + } + + /* Check for duplicate valid indices (skip check for idx=3D0) */ + if (unlikely(idx && __test_and_set_bit(idx, bitmap))) { + jfs_err("Duplicate index:%d in stbl in dtroot\n", idx); + return false; + } + } + + return true; +} diff --git a/fs/jfs/jfs_dtree.h b/fs/jfs/jfs_dtree.h index 1758289647a0..94dc16123c87 100644 --- a/fs/jfs/jfs_dtree.h +++ b/fs/jfs/jfs_dtree.h @@ -253,4 +253,6 @@ extern int dtModify(tid_t tid, struct inode *ip, struct= component_name * key, ino_t * orig_ino, ino_t new_ino, int flag); =20 extern int jfs_readdir(struct file *file, struct dir_context *ctx); + +extern bool check_dtroot(dtroot_t *p); #endif /* !_H_JFS_DTREE */ diff --git a/fs/jfs/jfs_imap.c b/fs/jfs/jfs_imap.c index 194cb05b42b9..7056c8d6fda2 100644 --- a/fs/jfs/jfs_imap.c +++ b/fs/jfs/jfs_imap.c @@ -3111,6 +3111,10 @@ static int copy_from_dinode(struct dinode * dip, str= uct inode *ip) =20 if (S_ISDIR(ip->i_mode)) { memcpy(&jfs_ip->u.dir, &dip->u._dir, 384); + if (!check_dtroot(&jfs_ip->i_dtroot)) { + jfs_err("Corrupt dtroot\n"); + return -EIO; + } } else if (S_ISREG(ip->i_mode) || S_ISLNK(ip->i_mode)) { memcpy(&jfs_ip->i_xtroot, &dip->di_xtroot, 288); } else --=20 2.34.1